This invention relates to the field of construction work, and comprises a new method and means for constructing concrete decks over spaced longitudinal beams of steel or concrete. While of general utility, my invention is most useful in bridge construction, and is illustrated in that use.
A well known way of constructing concrete decks which are to be upheld by longitudinal beams supported on columns or piers or in any other suitable fashion, involves supporting a plurality of straining members on the lower flanges of two spaced successive beams. Jack screws rest on each straining member near the ends thereof, and support timber bearers. The joists of the deck support sheathing are carried on the bearers: they lie parallel to the underlying beams and extend above them, as adjusted by the jack screws, to make the deck thickness greater over the beams than over the spaces between them. Sheathing panels are laid on top of the hoists, filler strips are added at the ends of the joists if necessary, and the concrete is poured and finished.
For installations where the transverse beams are of steel, it has often been necessary to use sacrificial members temporarily welded to the beams and later cut off and discarded: in a structure as large as a bridge, this becomes a not negligible element of cost and wastage.
After the concrete has set, the jack screws are loosened, so that the bearers allow the joists to move downward from the sheathing panels, the latter normally remaining in engagement with the undersurface of the concrete. The joists are removed, then the bearers, jack screws, and straining members, after which as many as possible of the sheathing panels and filler strips are salvaged for reuse.